There is no upper age limit on going solo, it's just on ability to handle the glider including emergencies. Most clubs have 70+ year-olds flying solo, many with people only starting after retirement and going on OK to solo.
For somebody starting off without experience, a typical number of launches to solo is 30 plus the number of years in your age (or up to double that for slow learners). With prior experience, it should be less - some bits you never forget, rather like riding a bike.
If you have time, go for a 5-day course - you will learn (re-learn) faster.
Equipment and teaching techniques are better than the old days.
If you can afford it, I would recommend aerotowing. Winch launches are very quick - the old brain finds it hard to keep ahead of the glider and monitor speed, attitude, sound, altitude etc., and react quickly enough and correctly when it goes wrong (as simulated cable breaks will prove all too well). Costs more per flight, but may well be as cheap overall or even cheaper, to get to acceptable solo standard. Just my opinion - others may disagree.
Chris N.